What similarities and differences do you see between functions and linear equations studied Are all linear equations functions? Is there an instance in which a linear equation is not a function?

(I understand that a function is a correspondence between a first set, called the domain, and a second set, called the range, such that each member of the domain corresponds to exactly one member of the range. And Linear equations can have more than one variable.)

How do you tie the main differences together?

I have to create an equation of a nonlinear function and provide two inputs for your classmates to evaluate.

This is the example given by my teacher..
A function must have each member of the domain (x value) mapped to only 1 value of the range (y value). For example,
(1,5)(2,6)(3,7)(4,8)(5,8)
Domain range
1 5
2 6
3 7
4 8
5 8